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Mike S.
Mike S., ASE Certified Technician
Category: Dodge
Satisfied Customers: 6703
Experience:  ASE certified
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Replaced the Alternator and swapped the battery to test the

Customer Question

Replaced the Alternator and swapped the battery to test the start function with a fully charged batt. It started right up.
JA: Will the headlights turn on? Is the battery fully charged?
Customer: Then put old battery in and tried to jump start due to low charge. Now it won't start... Just cranks and cranks but won't fire. My research says it might be related to the anti theft system. Is there a reset process?
JA: What is the model/year of your Dodge?
Customer: 2007 Durango
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Fully charged batt. All lights working
JA: Anything else you think the mechanic should know?
Customer: Hoping to reset and get started and avoid a tow to the dealer and a costly computer reprogram
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Dodge Mechanic about your situation and then connect you two.
Submitted: 3 months ago.
Category: Dodge
Expert:  -Brad- replied 3 months ago.

Good afternoon and welcome to JustAnswer!!

My name is ***** ***** I have worked for a Chrysler-Dodge-Jeep dealership for 19 years and I will do my best to help.

Do you see a red security light on in the dash? If so do you have another key to try? Is the check engine light on and if yes then post the codes here so I can see what's going on..

Talk soon,


Customer: replied 3 months ago.
I only have a regular factory key so no security fob - my wife lost it. A mechanic said no codes on the scanner but the engine light is illuminated. There is no security light on the dash.
Customer: replied 3 months ago.
Hunch is it's related to security lock-out issue.
Local mechanic put in new alternator. Then hooked up a new battery to test start and it fired right up. Then he removed the old battery while vehicle was running and it quit. He put in the old battery knowing he would need to jump start since it was so low in voltage. He hooked up the battery and when we tried to jump start it will just crank and crank but will not start.
Expert:  -Brad- replied 3 months ago.

If the check engine light is on then there are codes in the PCM and in order to know what's going on I will need to know the codes... Can I get your VIN to see if you have programmed keys?

Customer: replied 3 months ago.
Mechanic left and now I have no scanner. VIN is 1D8HB48P87F545541
Expert:  -Brad- replied 3 months ago.

2007 Bright Silver Metallic Durango with a 4.7 engine.. You do have a programmed key but if it was security it would show a red LED light on in the dash. At this point I will need to you to read the codes and post them here.. You can try installing a new fresh battery to see if that helps but if not I will need to know what codes are setting to help you get it fixed..

Customer: replied 3 months ago.
Well I will reply with codes once I can get a scanner on it. Not sure when that will be... Hopefully later today
Customer: replied 3 months ago.
Just scanned... No codes found. Guy said Engine light is on only because key is in "On" position.
Expert:  -Brad- replied 3 months ago.

If no codes then you will need to start with the basics and see if it has spark and fuel psi..

Customer: replied 3 months ago.
If it was/is a PCM issue, would it throw a code?
Expert:  -Brad- replied 3 months ago.

Yes there should be a code, but since there isn't lets see if it has fuel psi and spark and go from there..

Customer: replied 3 months ago.
It has fuel, it has spark and compression is good. The scanner is reading everything as it ought according to mechanic that was just here - no error codes whatsoever
Customer: replied 3 months ago.
Any other thoughts/suggestions appreciated
Customer: replied 3 months ago.
By the way - I may have failed to mention that after the alternator was replaced and the vehicle started, the mechanic disconnected the battery while it was running. My additional research indicates I may need to get the thing reprogrammed... Is there any kind of work-around?
Expert:  -Brad- replied 3 months ago.

Good morning, sorry for the delay!!

There is no programming needed when replacing the alternator.. Only modules need to be programmed when replaced and since it started and shut off when the battery was disconnected then the alternator may not be charging. If it has spark and fuel then it should start, and since it's not then your missing one or the other.. If you install a good battery will it start up?

Customer: replied 3 months ago.
Will not start with a good battery. I am afraid it's in some sort of anti theft mode... It just cranks and will not start. The programming I referred to would be due to disconnecting me the battery when the vehicle was running. Possible that something got messed up with the PCM or other electronics?
Customer: replied 3 months ago.
3.5 hours without a reply... If the vehicle is in anti-theft mode, will there definitely be a security indicator light on the dash? And is there any kind of reset without going to the dealer?
Expert:  Mike S. replied 3 months ago.

Spray a couple small shots of starting fluid into the throttle body and then quickly before it evaporates, see if the engine will start and run for a few seconds. If it does the ignition ad spark are ok and it is most likely fuel problem, however if it still don't start with the starting fluid, then we can assume the problem is with the ignition because the starting fluid will have substituted for the fuel system.

Let me know which it does, start and run for a few seconds or still not start.

Customer: replied 3 months ago.
Fuel pressure is good.... Checked it earlier. I also have spark - no doubt about it. Also can't be an ignition issue. The scanner shows all normal - no codes.
Only thing I am not sure of is if the injectors are firing. I sense that they may be disabled due to anti theft mode (if that's a possibility).
Expert:  Mike S. replied 3 months ago.

I assume you don't have any starting fluid, is that correct?

Other than that, you can purchase a fuel injector tester noid light and check for an injector pulse while cranking but I would have preferred trying the starting fluid test first.

Customer: replied 3 months ago.
I do not have starting fluid. I am in NC on 4x4 beaches... 10 hrs from home and 10 miles off the paved road.
Expert:  Mike S. replied 3 months ago.

How did you replace the alternator then if you are on an isolated beach?

Customer: replied 3 months ago.
Long story - local "mechanic" changed it out for me on site. Everything was fine until he disconnected battery cable while vehicle was running.
Expert:  Mike S. replied 3 months ago.

ok, the next step is either tow it home or try the starting fluid test and/or the noid light.

let me ask you this though, when you first turn the key to run, before you turn the key to start, can you hear the fuel pump run for 2 seconds?

Expert:  Mike S. replied 3 months ago.

You said you checked the fuel pressure, but was that before or after this no start?

Expert:  Mike S. replied 3 months ago.

If it was after, than it appears the pcm isn't supplying the fuel injectors with a pulse, so check the pcm fuses.

Customer: replied 3 months ago.
Fuel pump runs when key is turned on... The fuel pressure was checked after the "no start" issues.
PCM fuses have been checked and they are good. The guy is coming back in the AM with Noid light to test the injector pulse.
Let's assume there is no pulse - is there a solution other than a reprogram at the Dealer?
Expert:  Mike S. replied 3 months ago.

If there is no pulse, I don't think it's going to boil down to a reprogram, most likely something blew like a fuse or in rare instances the pcm got fried, exactly why on these modern vehicles with the voltage regulator and/or alternator controlled by the pcm or even in some circumstances the pcm is the voltage regulator why removing the battery cable while the engine is running even to test the alternator or for an other reason is a bad idea, cause the voltage could spike and fry something, in this case it may have just fried the pcm.

Expert:  Mike S. replied 3 months ago.

Yes, I double-checked and this is what the repair manual says "Electronic Voltage Regulator (EVR) circuitry within the Powertrain Control Module (PCM)". I would call a tow truck.

Customer: replied 3 months ago.
if indeed that's the case - only fix is by the dealer??
Expert:  Mike S. replied 3 months ago.

No, anyone with a scan tool can do it because the new or used pcm will most likely have to be programmed to the vehicle once it's installed.

Expert:  Mike S. replied 3 months ago.

have you decided what is your next step yet?

Customer: replied 3 months ago.
Noid test done - pulse is being sent to the injectors.
To recap - have fuel pressure, have spark, injectors firing, what are we missing?
Customer: replied 3 months ago.
Checked Compression with a gauge - Reading 90-120 with 4 of cylinders checked.
Any thoughts?
Expert:  Mike S. replied 3 months ago.

Sorry I'm o late to reply, didn't get to sleep until 8am.

That covers about everything except for bad gas and that is why I wanted to try the starting fluid in order to rule that out or not.

So you got a noid light but forgot the starting fluid?

Customer: replied 3 months ago.
Tried starting fluid too... No start.
Checked compression - all good. Pulled valve cover and all the rockers are doing their job.
Doesn't seem to be a timing issue either.
I am guessing we are dealing with a PCM issue - bad module somewhere.
Your thoughts??
Expert:  Mike S. replied 3 months ago.

Ok, so the fact that it still would not start up even for a few seconds on starting fluid indicates something other than the fuel system. You may eventually be looking at a timing belt. 90 psi is kinda low.

Customer: replied 3 months ago.
Agreed on the PSI... But the fact still remains that it started and purred like a cat until the battery (-) cable was disconnected while still running. I don't believe it's a timing chain issue.
I called a Dodge dealer in NJ that I dealt with in the past - when I told him what was happening and all that had been tested, he said he would bet with 90% certainty it is something with the PCM or a related module.
Expert:  Mike S. replied 3 months ago.

The pcm supplies the fuel injector pulse, turns on the fuel pump and may even help create the spark, none of these are missing. I would lean toward the spark plugs are gas fouled now because of the time it didn't start but was still spraying gasoline. Remove all the spark plugs and either clean and dry them, I use starting fluid, or carb cleaner or if they need replaced, just replace them all and try it again. Being you are so far away from a parts store, just clean them and dry them off. If you have nothing else use whatever you got to get the gas off.